1. Field of the Invention
The present invention relates to packaging of computing systems and more particularly to an electromagnetic compatibility (EMC) sealing apparatus and related method such as used in computing system environments.
2. Description of Background
The industry trend has been to continuously increase the number of electronic components inside computing systems. Unfortunately, while the numbers of these components are increased, the foot prints of these systems remain the same or are even reduced. This is because installation, transportation and storage issues of the consumers have to be addressed. Lighter, and more compact systems are often more attractive to potential consumers. Unfortunately, storing many components in a tight footprint, despite its many advantages, also creates challenges for the designer of these systems. Moreover, while increasing the components inside a simple computing system does create some challenges, such an increase in larger more sophisticated system environments create even greater problems.
A particularly challenging area for the designers of these systems is the issue of resolving electromagnetic interference (EMI). Every device or component emits a certain amount of electromagnetic radiation, also referred to as electromagnetic leakage. However, as the number of components is increased, electromagnetic leakage concerns continue to grow. In larger system environments, where the components are packaged in close proximity to one another, the increased number of components and the system footprint greatly increases the EMI concerns since the leakage from one device can greatly affect the proper function of a close by component. Consequently, unresolved EMI leakage can affect system performance, data integrity and speed of the entire system environment. This is because while such effects can be tolerated when few devices and components exist, the increasing number of components and devices can seriously impact system integrity and performance. In addition, many recent semiconductor devices that operate at higher speeds, cause even greater electromagnetic emission in higher frequency bands where interference is more likely to occur.
One way to address or minimize electromagnetic interference is through electromagnetic shielding. Electromagnetic shielding is the process of limiting the flow of electromagnetic fields between two locations, by separating them with a barrier made of conductive material. In addition, proper device operation and electromagnetic compatibility (EMC) requires that emissions from a given device be reduced by shielding or other similar means. Such shieldings are designed not only to reduce emissions from the device itself, but also to reduce sensitivity of the device to external fields such as fields from other devices. One type of such EMI shielding comprise EMI gaskets.
In many computing system environments, a metallic type of electromagnetic gasket is used to contain EMC emissions in an electrical enclosure in which a device having a printed circuit board or card assembly is engaged. In these cases, while the EMC emissions need to be contained when this card is plugged, it is desired for the gasket to be designed such as to allow the card to retract back into its chassis prior to plugging or when the card is removed from the system. Unfortunately, the prior art does not provide adequate solutions to allow for the easy retraction and removal of the card, especially when an EMC gasket is also included. It is therefore, desirable to have a total system that can provide for this while providing a superior electromagnetic shield.